Stable isotopes of antimony available from ISOFLEX
Isotope
Z(p)
N(n)
Atomic Mass
Natural Abundance
Enrichment Level
Chemical Form
Sb-121
51
60
120.903822
57.30%
>99.00%
Metal
Sb-121
51
60
120.903822
57.30%
>99.00%
Oxide
Sb-123
51
62
122.904215
42.70%
>98.00
Metal
Sb-123
51
62
122.904215
42.70%
94.00-98.00
Oxide
Antimony was recognized in compounds by the ancients and was known as a metal at the beginning of
the 17th century, possibly much earlier. Its name derives from the Greek words anti + monos, meaning
"not alone," and its symbol, Sb, comes from the Latin word stibium ("antimony"). Its most important
mineral is stibnite, which formed the basis of black eye makeup in biblical times.
The French chemist Nicolas Lémery conducted early studies on antimony chemistry. It is a silvery-white, brittle,
metallic element with a crystal system-hexagonal structure. It exists in two unstable allotropic forms – a yellow
modification and a dark-gray lustrous amorphous powder – both of which revert to crystalline form.
Antimony is stable in dry air, not readily attacked by moisture, but slowly oxidizes in moist air. Oxidation may result
under controlled conditions, forming tri-, tetra- and pentaoxides. Antimony reacts with sulfur, combining in all
proportions, forming tri- and pentasulfides. It is oxidized by nitric acid, forming a gelatinous precipitate of hydrated
antimony pentoxide. It does not react with cold dilute sulfuric acid; however, reaction occurs in hot concentrated
acid: an oxysulfate of indefinite composition and low acid-solubility is formed. It reacts with hydrofluoric acid to form
soluble antimony trifluoride and pentafluoride.
Antimony alloys have many commercial applications. The metal makes its alloys hard and stiff and imparts
resistance to corrosion; such alloys are used in battery grids and parts, tank linings, pipes and pumps. The lead
plates in lead storage batteries comprise 94% lead and 6% antimony. Babbit metal — an alloy of antimony, tin, and
copper — is used to make antifriction machine bearings. Alloys made from very high-purity-grade antimony with
indium, gallium and bismuth, are used as infrared detectors, diodes, Hall effect devices and thermoelectric coolers.
Properties of Antimony
Name
Antimony
Symbol
Sb
Atomic number
51
Atomic weight
121.75
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Standard state
Solid at 298 °K
CAS Registry ID
7440-36-0
Group in periodic table
15
Group name
Pnictogen
Period in periodic table
5
Block in periodic table
p-block
Color
Silvery lustrous gray
Classification
Semi-metallic
Melting point
630.5 °C
Boiling point
1635 °C
Thermal conductivity
24.00 W/(m·K)
Electrical resistivity
40.00 μΩ·cm
Electronegativity
1.82
Specific heat
207.00 J/(kg·K)
Heat of vaporization
195.20 kJ·mol-1
Heat of fusion
200.00 kJ·mol-1
Density of liquid
6.53 g/cm3 at 630.5 °C
Density of solid
6.697 g/cm3
Electronic configuration
[Kr]4d105s25p3
Atomic radius
1.41 Å
Covalent radius
Sb3+: 1.21 Å
Oxidation states
-3, 0, +3, +5
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